Linx Technologies LICAL-TRC-MT - Manual (Page 16)

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Legal Considerations
If the transcoder is to be used with a transceiver operating in the 260MHz
to 470MHz ISM band in the United States under Part 15.231, then there
are some legal requirements that need to be considered. The FCC requires
that the transmission control something, so the transcoder cannot be
used simply for passing data. The data lines and CONFIRM line must be
connected to something that turns on or off, such as a motor, LED, buzzer,
or display. Application Note AN-00128 goes into this in detail.
The transcoder has the ability to be automatically activated with the Write
Status Inputs command through the SIE. The FCC requires that any
automatic transmission cease within 5 seconds of activation. The MT
could exceed this time depending on the baud rate used, the options that
are enabled, and the number of packets that are sent. Figure 19 shows
the packet time at each baud rate with the various options enabled or
disabled. The designer needs to be aware of the time depending on the
options that are in use and adjust the packet counter in the command to
ensure that the total time does not exceed 5 seconds. Application Note
AN-00157 goes into the serial commands in more detail and Application
Note AN-00125 goes into the FCC regulations under Part 15.231.
Helpful Application Notes From Linx
It is not the intention of this manual to address in depth many of the issues
that should be considered to ensure that the modules function correctly
and deliver the maximum possible performance. As you proceed with your
design, you may wish to obtain one or more of the following application
notes which address in depth key areas of RF design and application of
Linx products. These application notes are available online at
www.linxtechnologies.com or by contacting Linx.
MT Series Transcoder MODE_IND Definitions
MODE_IND Signals Description
Receive Mode
ON for as long as the transcoder is receiving data from a
learned user. This only indicates authorized data reception, not
status output activation.
Create Address Mode
ON during address generation while the CRT/LRN line is HIGH,
then it flashes* when the CRT/LRN line is taken LOW. Once the
15-second timer expires or the CRT/LRN line is asserted again,
the MODE_IND line turns OFF.
Learn Mode
ON while the CRT/LRN line is held HIGH until taken LOW to
enter Learn Mode, then it flashes* for 15 seconds until the timer
expires or the CRT/LRN line is asserted again. If the 60th user
profile has been saved, it blinks* 5 times to indicate the next
user profile will overwrite the first.
Erase Mode
ON while the CRT/LRN line is held HIGH for 10 seconds and
Erase Mode is entered, then it turns OFF until the CRT/LRN
line is released. It then turns back ON again for 2 seconds to
indicate erase completion.
Serial Interface Mode
OFF while a command is being received (SER_IO = input) and
ON while an ACK/reply is being sent (SER_IO = output).
*Blink = ON for 1sec and OFF 250ms
*Flash = ON for 65ms and OFF for 65ms
Transcoder MODE_IND Definitions
The MODE_IND line is the primary means of indicating the state of the
transcoder to the user. The table below gives the definitions of the
MODE_IND signals.
Figure 22: MT Series Transcoder MODE_IND Definitions
Helpful Application Note Titles
Note Number Note Title
AN-00100 RF 101: Information for the RF Challenged
AN-00125 Considerations for Operation Within the 260–470MHz Band
AN-00128 Data and Bidirectional Transmissions under Part 15.231
AN-00157 Connecting to the Serial Interface on the MT Series Transcoders
AN-00310 Encoder and Decoder Comparison
AN-00320 The Basics of Remote Control and Remote Keyless Entry
Figure 23: Helpful Application Note Titles